I had/have this same problem. I've been noticing others with the same problem since the anniversary update. Funny enough, I can't connect to the server using my wan IP, but I can connect with my lan IP. My friends can all connect to my server via wan IP though. You should have one of your friends try to connect from outside your network, I have a feeling it'll work fine for them.
It's a frustrating issue though, and hopefully Nelson will post a fix.